The present invention relates to a scanning optical ranging system. It finds particular application in conjunction with a light detection and ranging (LIDAR) system and will be described with particular reference thereto. It will be appreciated, however, that the invention is also amenable to other applications.
A light detection and ranging (LIDAR) system transmits a pulse of light (e.g., from a laser), which is reflected from a target. An optical receiver detects the reflected light, and the range to the target is computed from the delay time between the transmission of the light pulse and the detection of the reflected light. The receiver field-of-view and the transmitted light beam are usually matched and co-aligned to ensure maximum light collection efficiency.
Targets at farther ranges typically result in reflected optical pulses having relatively lower intensities at the optical receiver. Therefore, optical background noise and receiver electronic noise detected by the optical receiver may incorrectly be viewed as additional pulses from the target. These spurious additional pulses tend to cause confusion and, therefore, may lead to inaccurate range determinations to the target. For example, these additional pulses may result in false triggers at the optical receiver. Increasing power of the optical pulse tends to also increase other non-liner effects in the laser and introduce more background noise.
The present invention provides a new and improved LIDAR system which addresses the above-referenced problems.